Earticle

한국전자통신연구원은 위성항법의 다양한 응용프로그램과 항법알고리즘을 위한 시험 및 평가환경을 제공하는 소프트웨어 위성항법 이산화 IF 신호시뮬레이터를 소프트웨어 기반 GNSS 공공활용기술통합검증시스템 개발 과제의 일환으로 개발하고 있다. 소프트웨어 위성항법 신호시뮬레이터는 GPS 및 갈릴레오 디지털신호를 제공하게 된다. 본 논문에서는 이러한 소프트웨어 위성항법 이산화 IF 신호 시뮬레이터의 요구사항 및 개념설계에 대하여 기술하고 있다.

Software GNSS digitized IF signal simulator is being developed by ETRI as a part of development of software-based GNSS Test & evaluation Facility which will provide test and evaluation environment for various software level application and navigation algorithm in GNSS. Software GNSS IF signal simulator will provide digitized GNSS signal including GPS and Galileo. The requirement analysis and conceptual design for the Software GNSS IF signal simulator is presented in this paper.

본 연구는 대면적 평판형 엑스선 검출기를 통해 획득한 혈관조영 프로젝션 영상의 화질을 평가하여 제조 사마다 독립적으로 사용 중인 품질보증프로그램을 서로 검증할 수 있는 기초자료를 제공하고자 하였다. IQST 팬 텀을 기반으로 매개변수들을 조절하여 프로젝션 영상을 획득하였으며, 영상분석 프로그램은 Image J를 사용하였 다. 획득한 영상에서 신호/잡음 성능, 저/고 대조도, 알루미늄 스텝웨지 속성을 분석하기 위해 신호, 잡음 등을 측 정하였다. 그 결과 kV의 증가는 영상에서 신호와 잡음이 동시에 증가하였으며, Dose의 증가는 영상에서 잡음을 감소시켰다. 그리고 EE-Kernel 크기의 증가는 영상의 경계 강조와 함께 경계 주위의 잡음 또한 함께 강조시켰다. 향후에는 공간 주파수 상에서 대조도와 잡음을 분석할 수 있는 변조전달함수(MTF)와 잡음력스펙트럼(NPS)에 대 한 연구가 필요하다고 사료된다.

This study evaluated the image quality of angiography projection images obtained through a large-area flat-panel X-ray detector and attempted to provide basic data that can be used to verify quality assurance programs independently used by each manufacturer. Projection images were acquired by adjusting parameters based on the IQST phantom, and Image J was used as an image analysis program. In the acquired images, signal and noise were measured to analyze signal/noise performance, low/high contrast, and aluminum step wedge property. As a result, an increase in kV simultaneously increased signal and noise in the image, and an increase in Dose reduced noise in the image. In addition, the increase in EE-Kernel size emphasized the edges of the image and also emphasized the noise around the edges. In the future, it is believed that research is needed on the MTF and NPS, which can analyze contrast and noise at spatial frequency.

Because of the equivalence between control chart procedures and hypothesis testing, we propose to use likelihood ratio test (LRT) statistic Z2i as the multivariate control statistic for simultaneous monitoring means of the multivariate normal process. Properties and comparisons of the proposed control charts are explored and conducted for matched fixed sampling interval (FSI) and variable sampling interval (VSI) with two sampling interval charts. The result of numerical comparisons shows that EWMA chart with two sampling interval procedure is more efficient than the corresponding FSI chart for small or moderate changes. When large shift of the process has occurred, we also found that Shewhart chart is more efficient than EWMA chart.

본 연구의 목적은 재평가 결과 공시에 대한 시장의 반응이 재평가이익 또는 재평가 기업의 재무 특성에 따라 차별적인지를 검증하는 것이다. 한국채택국제회계기준(K-IFRS) 실시에 앞서 2009년-2010년 사이에 자산재평가를 실시한 유가증권시장의 제조기업 133개가 표본으로 사용되었다. 재평가 결과 공시에 따른 시장의 반응은 시장수익률조정 누적수익률(CMAR)과 위험조정 누적수익률(CRAR)을 사용하여 측정하였으며, 재무특성 사이의 관계는 다음과 같았다. 첫째, 재량적 발생액이 클수록 누적초과수익률은 낮게 나타났다. 이는 이익조정이 큰 기업일수록 시장의 반응이 부정적임을 의미한다. 둘째, 수익성(ROA)은 초과수익률과 유의적인 양(+)의 관계를 보였다. 수익성이 좋은 경우 재무구조 개선의 필요성이나 이익조정의 가능성이 그만큼 낮을 것이므로 재평가는 시장에 긍정적인 정보를 전달하는 것으로 판단된다. 셋째, 재무위험과 초과수익률 사이의 관련성에 대한 가설과 달리 부채비율과 이자보상배율은 초과수익률과 관련성이 없는 것으로 나타났다. 이는 재무구조 개선에 따른 재무위험의 감소효과가 직접적인 것이 아니며 장기간 간접적으로 예상되는 불확실한 효과이기 때문으로 판단된다. 한편 재평가이익이 자산에서 차지하는 비중(DIFF)이 클수록 누적초과수익률은 낮게 나타났는데 그 관계는 통계적으로 유의성이 다소 낮았다. 이러한 실증 결과는 자산재평가가 기업의 경제적 실질에 영향을 미치지 않고 순이익에 영향을 미치지 않는 사건임에도 불구하고 자산재평가가 자산재평가 기업의 재무적 특징에 대한 정보를 시장에 전달함을 의미한다.

The purpose of this study is to test market response on the information of asset revaluation. As K-GAAP adopted asset revaluation in 2008 before K-IFRS became obligatory in 2011, many of companies achieved the reduction effect of leverage ratio. Test period is from 2009 to 2010. Revaluation samples are 133 firms, which were selected form public, manufacturing firms. And market response was measured by cumulative market-adjusted rate of return and cumulative risk-t-adjusted rate of return around the event day, which means the announcing day of revaluation surplus. The empirical results showed that there was negative relation between cumulative abnormal return and revaluation surplus ratio or discretionary accounting accruals. And there was positive relation between cumulative abnormal return and return on total asset. But there was no relation between cumulative abnormal return and financial risk measured by leverage ration and interest compensation ratio. As revaluation surplus is not recorded as components of earnings but included in net asset directly, asset revaluation doesn't have a economic effect on value, But the empirical results imply that the information of asset revaluation transfer the signal related to value to the market.

위성항법 시스템의 무결성을 확보하기 위해서는 다양한 위성 신호 모니터링 체계가 필요하며, 그중 SQM (signal quality monitoring)은 위성 하드웨어 결함으로 인해 발생하는 EWF (evil waveform)의 탐지를 담당한다. 기존 연구에서 다룬 SQM 기법과 EWF의 TS (threat space) 정의 방법론은 주로 보강항법시스템을 고려하여 개발되었다. 그러나 차세대 지역위성항법시스템 (N-RNSS; next generation regional navigation satellite system)은 보강 시스템이 없는 환경에서 운용될 것을 가정하기 때문에 기존 연구를 기반으로 N-RNSS 신호에 적합한 새로운 TS 정의와 SQM 기법을 개발할 필요가 있다. 본 논문에서는 신호 왜곡 모델과 TS 정의 방법론에 대한 기존 연구를 요약하고, N-RNSS 감시국의 가정과 조건에 따라 N-RNSS 신호에 맞는 SQM 기법 개발 계획을 제안한다.

To ensure the integrity of satellite navigation systems, various satellite signal monitoring mechanisms are required, among which Signal Quality Monitoring (SQM) is responsible for detecting Evil Waveforms (EWF) caused by satellite hardware faults. Existing research on SQM techniques and methodologies for defining the Threat Space (TS) of EWF has primarily been developed with augmentation systems in mind. However, the next-generation Regional Navigation Satellite System (N-RNSS) will work without augmentation systems. This means that new TS definitions and SQM techniques must be created that are specifically for N-RNSS signals. This paper summarizes prior research on signal distortion models and TS definition methodologies, and proposes development plans for SQM techniques suitable for N-RNSS signals based on the assumptions and conditions of N-RNSS monitoring stations.

차량용 강우센서는 강우에 따라 와이퍼의 동작 속도를 제어하기 위해 만들어졌다. 따라서 강수의 많고 적음을 대략적으로 판단하여 와이퍼의 속도단계를 결정하기 위한 장치이다. 하지만 기술의 발달로 인하여 강우센서의 성능이 개선됨에 따라 와이퍼의 속도단계 결정 외에 강우량의 크기를 좀 더 정확히 판단할 수 있는 기술이 개발되고 있다. 본 연구에서는 강우입자로 인한 빛의 산란을 이용한 강우계측 방법을 이용하였다. 센서에서 광신호를 보내고 전면부 유리창에 반사되어 돌아오는 광신호를 이용하는 방법으로 물방울 입자가 커지면 빛의 산란으로 센서의 광 감지량이 줄어들게 된다. 강우량의 정확도를 높이기 위하여 강우센서의 검지면적과 검지채널을 기존 강우센서에 비해 크게 확장하였다. 또한 센서의 감지 신호(Signal)를 강우량으로 환산하기 위하여 실내 강우발생 실험 장치를 이용하여 와이퍼의 속도단계(W)에 따른 특정 강우(R) 발생시 센서 감지량(S)과의 관계를 이용한 W-S-R 관계식을 개발하였다. 이 관계식을 통하여 차량 강우센서의 신호체계를 실제 강우량으로 환산하여 사용자에게 제공한다면 차량관측망이 강우측정망이 되어 실제 강우측정망보다 고해상도의 강우정보를 생산할 수 있을 것으로 판단된다.

A vehicle rainfall sensor is made to control the operating speed of wipers depending on rainfall. Therefore this is the apparatus to determine the velocity phase of the wipers roughly based on the amount of rainfall. However, the technology which can judge the size of rainfall amount besides determining speed level of the wipers is developing according to the development of the function of rainfall sensor due to the development of technology. In this study, a rainfall measurement by using light scattering by precipitation particles was used. This measurement is to use light signal reflection from front glass and the bigger particle is the less detection of light by light scattering. The detection area of the rainfall sensor and detection channel were extended sizes to increase the accuracy of the rainfall. Also the W-S-R relational expression was developed by using a relationship between the specific precipitation (R) and the amount of sensor detection (S) when there is speed change of the wipers (W) and an indoor rainfall apparatus was used to convert sensing signal to rainfall. The signal system of vehicle rainfall sensor can be converted to the actual rainfall amount by using this formula and if this is provided to users then the vehicle observation network can produce higher-resolution than actual observation network can be produced.

본 연구에서는 성인기 초반에 있는 대학생 118명을 대상으로 나트륨 섭취를 간단하게 평가할 수 있는 소변 중 salt signal을 사용하여 나트륨 섭취량을 추정하고 이에 따른 나트륨 섭취 관련 식행동 및 식태도를 조사하였으며, 그 결과는 다음과 같다. 연령 및 신체계측 분석 결과 소변 중 salt signal에 따른 과잉섭취군의 경우 남자 대상자의 비율이 적정섭취군에 비해 유의적으로 높았으며 수축기혈압이 높은 경향을 보였다. 또한 체질량지수는 두 군간 유의한 차이를 보이지 않았으며 생활습관 조사 결과 과잉섭취군의 경우 음주를 하는 비율이 적정섭취군에 비해 유의적으로 높게 나타났다. 나트륨 관련 식태도에 대해 분석한 결과 11가지 항목에 대한 식태도 총 점수는 적정섭취군과 과잉섭취군에서 각각 35.50점과 33.45점으로 적정섭취군이 과잉섭취군에 비해 긍정적인 나트륨 관련 식태도를 가지는 것으로 나타났다(P<0.05). 나트륨 관련 식행동에 대해 분석한 결과 식행동 총점은 소변 중 salt signal에 따른 두 군간 유의한 차이를 보이지 않았다. 그러나 나트륨 관련 영양지식을 조사한 결과 나트륨 관련 영양지식 총점에서 12점 만점 중 적정섭취군이 9.77점으로 과잉섭취군의 8.82점에 비해 유의적으로 높은 점수를 보였다(P<0.05). 소변 중 salt signal과 나트륨 관련 식태도, 식행동 및 영양지식과의 상관관계를 분석한 결과 연령, 성별 및 체질량지수를 보정했을 때 소변 중 salt signal에 따른 소금 함량은 나트륨 관련 식태도 총점과 음의 관련성을 보였다. 이상의 연구 결과를 종합하여 볼 때 대학생에서 소변 중 salt signal에 따라 과다한 소금 섭취를 보인 대상자의 경우 적정섭취를 보인 대상자에 비해 나트륨 관련 식태도가 좋지 않고 영양지식도 낮은 것으로 나타났다. 이와 같은 결과를 통해 소변 중 salt signal로 추정한 나트륨 섭취와 나트륨 관련 식행동과의 관련성을 제시할 수 있었다.

The purpose of this study was to evaluate salt-related dietary attitudes, behaviors, and nutrition knowledge according to urinary salt signal of university students. Based on urinary salt signal, we classified subjects into an "adequate Na intake (ANI)" group (n=52) (salt ${\leq}6g$) and "excess Na intake (ENI)" group (n=66) (salt >6 g). Subjects were asked about general characteristics, lifestyle, salt-related dietary attitudes, behaviors, and nutritional knowledge using questionnaire. The ENI group had more subjects who were drinkers (P<0.05) compared to the ANI group. The ENI group (33.45) showed a significantly lower score in terms of salt-related dietary attitudes compared to the ANI group (35.50) (P<0.05). There was no significant difference in the total score of salt-related dietary behavior between the groups. The score of nutrition knowledge was significantly higher in the ANI (9.77) group than in the ENI (8.82) group (P<0.05). The correlation analysis indicated that the urinary salt signal had a negative correlation with the salt-related dietary attitude score after adjustments for age, sex, and body mass index (r=-0.2100, P<0.05). These results support the validity of using the urinary salt signal to simplify estimation of sodium intake.

The hybrid teaching approach of "MOOC + SPOC + Flipped Classroom" overcomes the constraints of time and space that are typically associated with traditional teaching methods, thus compensating for the shortcomings of traditional approaches. These changes in education are driven by the "Internet+" wave and the growing popularity of online teaching. The "MOOC + SPOC + Flipped Classroom" hybrid teaching mode can successfully compensate for the drawbacks of traditional teaching methods, thereby overcoming their restrictions. By defining relevant concepts, one can distill the key characteristics of the "MOOC + SPOC + Flipped Classroom" hybrid teaching mode. Formative assessment was employed to thoroughly evaluate the effectiveness of this teaching approach. By leveraging the advantages of massive open online course (MOOC), small private online course (SPOC), and flipped classroom, the "MOOC +SPOC + Flipped Classroom" teaching mode incorporates real-time student assessment through peer evaluation, computer-aided evaluation, and teacher evaluation. This mode promotes the simultaneous development of theoretical knowledge and practical skills, helping students to establish strong foundations while fostering their practical abilities. While the traditional teaching method remains fruitful, the convenience of today's network allows the teaching profession to continually evolve. The traditional teaching mode heavily relies on teachers, making it impossible to conduct lessons without them. However, the development of MOOC enables students to seek knowledge online from their preferred teachers, rather than solely relying on their assigned instructors.

Here we propose a new signal set design for physical cell identification (PCI) in sub-THz OFDM systems. We also derive useful properties of proposed signal set, which can be employed to assign PCI and reduce interference. The proposed signal set is easy to generate because it is designed using binary m-sequences. These sequences exhibit the relationship of being preferred pairs to each other. The performance of the proposed signal set is similar to that of the secondary synchronization signal (SSS) for 5G NR, but the possible number of signal set is much larger than that of SSS for 5G NR. Furthermore, the proposed signal set contains SSS for 5G NR and a binary Gold sequence set as subsets. The proposed signal set can provide approximately 100 times more signals than the SSS of 5G NR. The signal to noise ratio (SNR) loss of the proposed signal is less than 1 dB for 4 times more sequences relative SSS of 5G NR and less than 2 dB for 25 times more sequences than the SSS of 5G NR.

Maximum likelihood (ML) is the best estimator asymptotically as the number of training samples approaches infinity. This paper deduces an adaptive algorithm for blind signal processing problem based on gradient optimization criterion. A parametric density model is introduced through a parameterized generalized distribution family in ML framework. After specifying a limited number of parameters, the density of specific original signal can be approximated automatically by the constructed density function. Consequently, signal separation can be conducted without any prior information about the probability density of the desired original signal. Simulations on classical biomedical signals confirm the performance of the deduced technique.

Background: Manganese (Mn) has been found to increase the signal intensity of the globus pallidus (GP) on T1-weighted magnetic resonance images (MRI). We performed this study in order to determine the features of liver disease that correlate with pallidal signal intensities. Methods: We assessed blood Mn levels and pallidal signals in T1-weighted MRI in 49 patients with liver cirrhosis and 23 healthy controls. Results: Increased signal intensity in the GP was observed in 30 of 49 (61.2%) patients with liver cirrhosis, with the pallidal index (PI) in patients with Child-Pugh classes B and C differing significantly from the PI in controls. Multiple linear regression analysis showed that blood Mn concentrations and Child-Pugh scores in cirrhotics were significantly associated with increased PI after controlling for other confounders (p<0.05 each). Conclusions: Pallidal signals on T1-weighted MRI are mainly observed in advanced liver cirrhosis. The present study suggests that advanced liver cirrhosis may be a human model for manganism.

Korean mistletoe lectin (KML) is the major component found in Viscum album var. (coloratum), displaying anti-cancer and immunostimulating activities. Even though it has been shown to boost host immune defense mechanisms, the regulatory roles of KML on the functional activation of macrophages have not been fully elucidated. In this study, regulatory mechanism of KML on macrophage-mediated immune responses was examined in terms of KML-mediated signaling event. KML clearly induced mRNA expression of tumor necrosis factor (TNF)-$\alpha$, the generation of reactive oxygen species (ROS) and phagocytic uptake in RAW264.7 cells. All of these events were strongly suppressed by U0126, whereas TNF-$\alpha$ mRNA was not diminished by SB203580 and SP600125, indicating ERK as a central enzyme managing KML-induced up-regulation of macrophage functions. Indeed, KML strongly induced the phosphorylation of ERK in a time-dependent manner without altering its total level. Therefore, these data suggest that ERK may be a major signaling enzyme with regulatory property toward various KML-mediated macrophage responses.

Lactic acid bacteria (LAB) are considered as probiotics with immunostimulatory property. In this study, we investigated the molecular mechanism of its immunostimulating potency on macrophages using combined preparation of LAB (cpLAB). cpLAB is able to strongly stimulate nitric oxide (NO) production as well as inducible NO synthase (iNOS) expression from macrophage-like RAW264.7 cells. The cpLAB-induced NO release seemed to be mediated by extracellular signal-regulated kinase (ERK) but not p38 and C-Jun N-terminal kinase (JNK), since U0126, an ERK inhibitor, clearly suppressed NO production. cpLAB significantly diminished the binding of toll like receptor (TLR)-2 antibody up to 25%, implying that cpLAB-mediated activation of macrophages may be required for the functional activation of TLR-2, but not TLR-4. Therefore, our data suggest that cpLAB may directly allow macrophages to immunostimulating potency via activation of TLR-2 and ERK.

The cognitive radio communication is taking the attentions because the development of the technique came to be possible to analyze wireless signals. In the IEEE 802.22 WRAN Systems[1], how to detect a spectrum and signals is continuously studied. In this paper, we propose the efficient signal detection method using SCF (Spectral Correlation Function). It is easy to detect the signal feature when we are using the SCF. Because most modulated signals have the cyclo-stationarity which is unique for each signal. But the fading channel effected serious influence even though it detects the feature of the signal. We applied LMS(Least Mean Square) filter for the compensation of the signal which is effected the serious influence in the fading channel. And we analyze some signal patterns through the SCF. And we show the unique signal feature of each signal through the SCF method. It is robust for low SNR(Signal to Noise Ratio) environment and we can distinguish it in the fading channel using LMS Filter.

In this paper, the effect of time difference of arrival (TDoA) is investigated for distributed nodes in OFDMA-based wireless mesh networks (WMNs). In order to minimize the interferences caused by TDoA in WMNs, the optimal starting point of FFT window at the receiver side of a node is derived by maximizing the effective SINR for each subcarrier. Also, a signal detection technique, called two dimensional ordered successive interference cancellation (TD-OSIC), is proposed for WMNs with TDoAs. It was shown via simulation that the proposed technique can achieve effective SINR and BER performances similar to the ideal case (no TDoA), even in WMNs with large TDoAs.

With advancements in information technology, traffic signal control has become a crucial component of smart transportation systems, and research based on reinforcement learning (RL) for this purpose is being actively conducted. However, tuning the weights of a multi-objective reward function remains a challenging task. This paper proposes an algorithm that leverages a large language model (LLM) to dynamically adjust the weights of the RL reward function in real time, enabling efficient traffic signal control at intersections. We compare the performance of dynamic weight adjustment via LLM and evaluate the signal control efficiency of the proposed model under various weather conditions.

Nitric oxide (NO) is a signaling molecule that plays a crucial role in numerous cellular physiological processes. In the skin, NO is produced by keratinocytes, fibroblasts, endothelial cells, and immune cells and is involved in skin functions such as vasodilation, pigmentation, hair growth, wound healing, and immune responses. NO modulates both innate and adaptive immune responses. As a signaling molecule and cytotoxic effector, NO influences the function of immune cells and production of cytokines. NO is a key mediator that protects against or contributes to skin inflammation. Moreover, NO has been implicated in skin sensitization, a process underlying contact dermatitis. It modulates the function of dendritic cells and T cells, thereby affecting the immune response to allergens. NO also plays a role in contact dermatitis by inducing inflammation and tissue damage. NO-related chemicals, such as nitrofatty acids and nitric oxide synthase (NOS) inhibitors, have potential therapeutic applications in skin conditions, including allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD). Further research is required to fully elucidate the therapeutic potential of NO-related chemicals and develop personalized treatment strategies for skin conditions.

The health of the human heart is commonly measured using ECG (Electrocardiography) signals. To identify any anomaly in the human heart, the time-sequence of ECG signals is examined manually by a cardiologist or cardiac electrophysiologist. Lightweight anomaly detection on ECG signals in an embedded system is expected to be popular in the near future, because of the increasing number of heart disease symptoms. Some previous research uses deep learning networks such as LSTM and BiLSTM to detect anomaly signals without any handcrafted feature. Unfortunately, lightweight LSTMs show low precision and heavy LSTMs require heavy computing powers and volumes of labeled dataset for symptom classification. This paper proposes an ECG anomaly detection system based on two level BiLSTM for acceptable precision with lightweight networks, which is lightweight and usable at home. Also, this paper presents a new threshold technique which considers statistics of the current ECG pattern. This paper's proposed model with BiLSTM detects ECG signal anomaly in 0.467 ~ 1.0 F₁ score, compared to 0.426 ~ 0.978 F₁ score of the similar model with LSTM except one highly noisy dataset.

In this paper, a network-independent distributed relay sensor (RS) activating method is proposed for energy-efficient cooperative communications using RSs. To achieve this, we introduce a novel metric termed the signal contribution-to-noise contribution ratio and design the required instantaneous received signal strength at RS for each RS to independently determine the activation. Therefore, the proposed RS activation (i.e., adaptive cooperation) is readily enabled without significant signaling overhead in the networks. The numerical results indicated that the proposed RS activation strategy can improve the received signal-to-noise ratio at a destination sensor with fewer active RSs, extending the lifetime of the sensor network.